What's worth watching, and what might not be, in prime time on Wednesday.

This CW comic-book series returns for a second season with its Arrow hero – Stephen Amell's Oliver Queen – out of town and even more than usually out of sorts. But don't worry: By the time the episode ends, Arrow will be back at work in Starling City.

Rachel Dratch, who has not had the post-SNL TV career her fans had hoped or her talents deserve, shows up on this terrific family comedy as Brick's principal. Brick, it turns out, has stopped attending classes – a new annoyance for a bedeviled but incredibly funny pair of parents whose older son has stopped sleeping in his dorm room.

Modern Family | ABC, 9 ET/PT

TV's current Emmy champion hits the 100th episode mark with a visit from Cam's sister Pam (Dana Powell), who doesn't know he's engaged to Mitchell. As it turns out, there's something Cam doesn't know about Pam, either. If you haven't been watching this season, here's what you should know: The engagement has given Modern a lift by giving Cam and Mitchell a new common purpose. The writers even seem to have increased those moments where the couple shows affection, a welcome move for those who prefer happy couples as the scenes help soften some of Mitchell's insults. There are, obviously, many real-world couples who behave worse than Cam and Mitch, but people usually grow tired of spending time with them.